Of course it's easy to say it now, and The Station will accept any email guff on this topic in retrospect: There was no way in heck that Microsoft was ever going to corral Yahoo -- from Day One. We never wrote here about it, but we told a number of people, and you all know who you are ...
Why? Culture clash, big time. It's not that the two companies couldn't have helped each other businesswise -- on paper, it made sense. But the fact is, and everybody knows this: The leadership and staffs never would have worked comfortably together.
Microsofties and Yahooligans have always approached IT and the Internet from completely different points of view. They certainly use their brains, but they specialize in using different parts of them.
Microsoft's first goal: Profit through proprietary IP; always has been its goal, always will be. Yahoo's first goal: Quality products through open source development; profit certainly a close second, but second nonetheless. Cats versus dogs, cool versus way cool, oil versus water.
A theoretical example: At the annual holiday party, Gates/Ballmer probably would hire Elton John or Sting to entertain. Jerry Yang probably would hire John Mayer or Adam Duritz. Both parties would be smashing, but they would have entirely different atmospheres.
'Nuff said. Let's move on.